Some prior art solutions are known. For example, U.S. Pat. No. 5,336,107 discloses a device for retaining an electrical plug and extension cord to another plug and extension cord employs fastener strip elements secured to the cord adjacent to the plug by a circumferential clamping element. When the electrical plug is engaged with a corresponding socket, the mechanical fastener elements secured to the plug engage cooperating fastening elements affixed to the corresponding socket to retain the assembly in its connected state.
The aim of the prior art solution is to keep the plug and the socket firmly attached. A problem related to the above-mentioned device is that it requires a counterpart, i.e. both the plug and the socket have to have fastener elements that fit to each other.